The present invention relates to a laser operating system for performing surgical operation by projecting a laser beam for treatment, and in particular to a laser operating system for adequately and automatically adjusting brightness of a sighting laser beam to align the laser beam for treatment to an affected site to be treated.
In a laser operating system for medical use, a sighting laser beam is projected for adequately aligning a laser beam for treatment to an affected site to be treated, and the treatment laser beam is aligned by the sighting laser beam.
In general, the laser beam is guided via an optical fiber and a delivery optical system and is projected toward the affected site. A system shown in FIG. 5 is used as the delivery optical system for the laser beam.
In FIG. 5, reference numeral 1 indicates a dichroic mirror. At positions facing to the dichroic mirror 1, a treatment laser oscillator 2 and a sighting laser oscillator 3 are provided. The treatment laser beam 4 emitted from the treatment laser beam oscillator 2 passes through the dichroic mirror 1 and is projected to the affected site to be treated by the delivery optical system 6. A sighting laser beam 5 emitted from the sighting laser oscillator 3 is reflected by the dichroic mirror 1 and is then projected to the affected site by the delivery optical system 6.
The delivery optical system 6 is used to guide the laser beam to the affected site, and it comprises a condenser lens 7 for converging the treatment laser beam 4 and the sighting laser beam 5 to an incident end of the optical fiber, an optical fiber 8 for guiding the treatment laser beam 4 and the sighting laser beam 5, a first lens unit 9 for turning the laser beam projected from the optical fiber 8 to parallel beams, a second lens unit (zoom variable power mechanism) 10 for changing a focusing position and magnification of the laser beam, and a third lens unit 11 for focusing the laser beam.
In the delivery optical system 6 as described above, the affected site is specified by the sighting laser beam 5 projected from the sighting laser oscillator 3. When the affected site is specified, i.e. alignment is completed, the treatment laser beam 4 is projected to the affected site from the treatment laser oscillator 2. By high density thermal energy of the treatment laser beam 4, photocoagulation or incision is performed at the affected site. By moving the second lens unit 10 in the direction of the optical axis, a diameter of the spot of the laser beam at the projected position can be changed.
As described above, in the laser operating system of this type, the treatment laser beam and the sighting laser beam are projected coaxially via the same optical system. In this respect, when the spot diameter of the treatment laser beam is adjusted, the spot diameter of the sighting laser beam is also changed.
Even when the output of the sighting laser beam is adjusted by an operator at first so that the sighting can be performed with adequate brightness, if the spot diameter of the treatment laser beam is increased later, output of the sighting laser beam per unit area at the affected site (hereinafter referred as xe2x80x9coutput densityxe2x80x9d) is decreased. As a result, the sighting laser beam is weakened and become dark, and it is difficult to see. On the contrary, when the spot diameter is set to a smaller value, the output density is increased. As a result, the sighting laser beam is too dazzling to see. For this reason, it has been necessary in the past for the operator to manually re-adjust the output of the sighting laser beam each time the spot diameter of the treatment laser beam is adjusted.
It is an object of the present invention to provide a laser operating system, by which it is possible, even when the setting of the spot diameter of the treatment laser beam is changed, to automatically adjust the output of the sighting laser beam in adequate manner in association with the change of setting and to perform sighting with adequate brightness at all times.
To attain the above object, the laser operating system according to the present invention comprises treatment laser beam projecting means for projecting a treatment laser beam to an affected site to be treated, sighting laser beam projecting means for projecting a sighting laser beam for aligning the treatment laser beam to the affected site, and adjusting means for adjusting a spot diameter of the treatment laser beam, wherein output of the sighting laser beam projecting means is adjusted in association with adjusting operation of the adjusting means. Also, the present invention provides the laser operating system as described above, wherein the output of the sighting laser beam projecting means is adjusted in such manner that output density of the sighting laser beam at the affected site is maintained approximately at constant level regardless of the adjusting operation of the spot diameter. Further, the present invention provides the laser operating system as described above, wherein output density of the sighting laser beam at the affected site is displayed. Also, the present invention provides the laser operating system as described above, wherein the output of the sighting laser beam is displayed. Further, the present invention provides the laser operating system as described above, wherein two modes can be selected, i.e. a mode without adjustment of associated operation and a mode with adjustment of associated operation.